Assay devices

• US 6,187,269 B1
• Filed: 03/15/1996
• Issued: 02/13/2001
• Est. Priority Date: 03/17/1995
• Status: Expired due to Term

• Current Assignee: Inverness Medical Switzerland GmbH (Abbott Laboratories Incorporated)
• Original Assignee: Unipath Limited (Abbott Laboratories Incorporated)
• Inventors: Lancesseur, Didier, Wiles, Stewart John
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US08/616,566
• Time in Patent Office: 1,796 Days
• Field of Search: 422/56, 422/58, 422/61, 436/165, 436/169
• US Class Current: 422/401
• CPC Class Codes: B01L 3/502 with fluid transport, e.g. in multi-compartment structures centrifugal-type cuvettes G01N21/07; analysis by separation into components G01N30/00; automatic analysers G01N35/00
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing

Abstract

Storage stability of an assay device, comprising an assay strip and sensitive reagents such as antibodies within a plastics casing, is maintained by moulding some or all of the casing from dessicant-containing plastics material, especially a blend of about 60-65% polystyrene and about 30% silica dust. Ideally the desiccant-containing plastics material is used in the moulding of a removable cap for the device. The cap can be made by sandwich injection moulding, using the dessicant-containing polystyrene as a core, surrounded by conventional polystyrene.

Claims

1. An assay device packaged within a sealed moisture-impervious wrapping, said assay device consisting essentially of:

a) a casing;

b) an assay strip within said casing together with at least one reagent in the dry state which can participate in a specific binding reaction to reveal an assay result following application of a sample liquid to said device, said casing having means whereby the sample liquid can be applied directly or indirectly to said strip; and

c) a removable cap or shroud to protect said sample liquid application means, said cap or shroud comprising a molded desiccant-containing plastics material incorporating desiccant in an amount sufficient to enhance storage stability of said reagent.

2. A device according to claim 1, wherein said desiccant-containing plastics material is enrobed or shielded within non-desiccant-containing plastics material.

3. A device according to claim 1, wherein said desiccant-containing plastics material comprises a blend of polystyrene and silica gel, and said enrobing plastics material comprises polystyrene.

4. A device according to claim 1, wherein said cap or shroud is manufactured by a process involving sandwich injection moulding.

5. A device according to claim 1, wherein said dessicant-containing plastics material consists essentially of a mouldable blend of:

a) about 60 to 65% by weight of a thermoplastic or thermosetting polymer; and

b) about 30% by weight of powdered dessicant;

the remainder of said dessicant-containing plastics material comprising one or more minor components selected from the group consisting of elastomers, fibrous materials, plasticisers, stabilisers, dyes and pigments.